Android layout searchView'；s输入的文本不可见

工具栏中的my searchView未显示searchView文本框中的文本请参见下图：

当我输入文本时，光标正在移动，如下图所示，但文本不可见

但是，当我选择输入的文本时，现在您可以看到输入的文本，用于折叠searchView的图标也不可见（在searchView的左侧）知道为什么会发生这种情况吗

我的xml文件：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/action_search"
        android:icon="@drawable/icon_search"
        app:actionViewClass="android.support.v7.widget.SearchView"
        app:showAsAction="ifRoom|collapseActionView"
        android:title="Search"/>

</menu>

---

多亏了

url函数：

public static <V extends View> Collection<V> findChildrenByClass(ViewGroup viewGroup, Class<V> clazz) {

    return gatherChildrenByClass(viewGroup, clazz, new ArrayList<V>());
}

private static <V extends View> Collection<V> gatherChildrenByClass(ViewGroup viewGroup, Class<V> clazz, Collection<V> childrenFound) {

    for (int i = 0; i < viewGroup.getChildCount(); i++)
    {
        final View child = viewGroup.getChildAt(i);
        if (clazz.isAssignableFrom(child.getClass())) {
            childrenFound.add((V)child);
        }
        if (child instanceof ViewGroup) {
            gatherChildrenByClass((ViewGroup) child, clazz, childrenFound);
        }
    }

    return childrenFound;
}

公共静态集合findChildrenByClass（ViewGroup ViewGroup，Class clazz）{
返回gatherChildrenByClass（viewGroup、clazz、new ArrayList（））；
}
私有静态集合gatherChildrenByClass（ViewGroup ViewGroup、Class clazz、Collection childrenFound）{
对于（int i=0；i

public static <V extends View> Collection<V> findChildrenByClass(ViewGroup viewGroup, Class<V> clazz) {

    return gatherChildrenByClass(viewGroup, clazz, new ArrayList<V>());
}

private static <V extends View> Collection<V> gatherChildrenByClass(ViewGroup viewGroup, Class<V> clazz, Collection<V> childrenFound) {

    for (int i = 0; i < viewGroup.getChildCount(); i++)
    {
        final View child = viewGroup.getChildAt(i);
        if (clazz.isAssignableFrom(child.getClass())) {
            childrenFound.add((V)child);
        }
        if (child instanceof ViewGroup) {
            gatherChildrenByClass((ViewGroup) child, clazz, childrenFound);
        }
    }

    return childrenFound;
}